VX Gearbox Swap

[Geoff T]

I have recently swapped my S2 Monte final drive for a VX unit. 60 mph is now at 2850 rpm instead of the 3250 of the original final drive. (14/52)
The VX box has a taller 1st gear and the 3.2:1 final drive. All Beta final drives are interchangeable, but you should swap pinion and gear as a pair to aviod any mismatch and possible noise! Apart from the taller 1st gear, all Beta intermediate ratios are the same. You will need a good press to remove the gearsets if you are changing pinions. Mine were very tight to get off! I needed to swap out 2nd gear off the VX box as the synchro had died. (Only found out after I had installed it!)
I simply disassembled the VX box and swapped the gearsets into my Monte casings. The crownwheel just unbolts from the original diff carrier. You need to refit the Monte diff carrier with the original speedo drive as the VX one has a different ratio. You need to retain the Monte cases as the VX gear selector shaft is longer than the Monte one and will not fit the external linkages (too tall).
I am running a stock 2L with 40 DCNF's. Acceleration is not much slower, but highway crusing is much quieter, as well as better gas mileage! Interestingly, top speed is the same at 185 KPH, but at lower RPM. More top speed now requireds more horsepower! Taller 1st gear is not too much of a hassel, and I now use 4th gear round town instead of 5th.
You can actually remove the whole gearset with the gearbox fitted, although refitting the selector rods and detent balls can try your patience! 5th gear removal is a doddle, but you will need to beg / buy / steal / make the two peg spanners required to remove the gearshaft nuts. I made a set by grinding 4 pegs into a couple of suitable sized sockets. Time consuming, but they worked!

Geoff T
S2 Montecarlo

[DJ]

I am about to embark on this job for my Scorpion.

I have acquired an NOS VX gearbox and intend to use the entire VX box instead of swapping parts in because my Scorp's box has some noisy bearings.

The first question I have is regarding the clutch. I've been advised by Beta VX knowledgeables that I'll require a VX clutch. However, my understanding is that the only reason I would need a VX clutch is if I was using the VX flywheel, which I don't plan to do unless it's necessary. What did you use for a clutch? (I seem to remember that a Thema Turbo clutch is a bit more durable and recommended.)

Regarding the gear selector shaft. Is there no way to modify or fabricate an adapter to make the VX selector work without swapping out the shafts? I won't have my new box until Monday so I don't yet know what it looks like.

Thanks.

[nickp]

Hi DJ,
I've just done the same job also. Just to confirm - from the Monte/Scorp box you'll just need the casing, selector shaft,speedo drive, clutch arm/release bearing, 1 diff o/p shaft (this is not threaded for the driveshaft flange on the VX box).
From the VX box you'll need the whole internals - gearsets / diff assembly.
If your VX box is good (ie bearings / synchros) then the whole lot should drop straight into your Monte/Scorp casing no probs and work a treat.
For a clutch I used a Delta HF Turbo (140bhp) plate and cover but with a new Monte release bearing (Delta one's way different). These clutches are supposed to be stronger and do bolt straight to the Monte flywheel.
Good luck and beware those flying springs / balls :eek:

Cheers,
Nick

PS. Once built don't test gear selection 'til you have the end casing in place. 5th gear goes too far = springs/selector barrels pinging round the garage. Learn from someone elses mistakes, it's much easier :)

[Wallace]

If the springs and things do go flying out, then if you find one set on the floor, the other two willl be 120 degrees apart !

Guess how I know !!

[DJ]

Hi DJ,
I've just done the same job also. Just to confirm - from the Monte/Scorp box you'll just need the casing, selector shaft,speedo drive, clutch arm/release bearing, 1 diff o/p shaft (this is not threaded for the driveshaft flange on the VX box).
From the VX box you'll need the whole internals - gearsets / diff assembly.
If your VX box is good (ie bearings / synchros) then the whole lot should drop straight into your Monte/Scorp casing no probs and work a treat.
For a clutch I used a Delta HF Turbo (140bhp) plate and cover but with a new Monte release bearing (Delta one's way different). These clutches are supposed to be stronger and do bolt straight to the Monte flywheel.
Good luck and beware those flying springs / balls :eek:

Cheers,
Nick

PS. Once built don't test gear selection 'til you have the end casing in place. 5th gear goes too far = springs/selector barrels pinging round the garage. Learn from someone elses mistakes, it's much easier :)

Thanks, Nick

But why would I need to swap things to the Scorp/Monte casing? This box should bolt right onto the engine. The only difference I can find is that the VX gear selector shaft is 1/4 inch taller than the shaft on the Scorpion box. I haven't looked at it in sufficient detail yet but at this point I believe I can get by with a simple spacer under the gear selector plate,

[DJ]

Just realized I won't need the VX gear after all. For some reason I was thinking it was driven off the VX final drive gear but it's not.

I'll be using my Scorpion diff and simply bolting on the VX ring gear so things should be peachy.

[Wallace]

You don't have to use a monte housnig - but you can't use a vx one without modification - not difficult though.

Three holes which support the clutch bracket need threading to M8.

The main sleector shaft is a different diameter so the journal it goes into needs reaming out with an adjustable reamer to be a nice fit. You can't get drilling it - it does need to be accurate !!

[DJ]

Three holes which support the clutch bracket need threading to M8.

Yep. Already planned for this and not a problem.


The main sleector shaft is a different diameter so the journal it goes into needs reaming out with an adjustable reamer to be a nice fit. You can't get drilling it - it does need to be accurate !!

I believe you're referring to the bottom of the Scorpion/Montecarlo selector shaft being a larger diameter.

I'm not yet convinced that I can't just use the VX shaft as-is. The only difference I've been able to determine upon cursory examination is that the VX shafter is slightly longer at the top. A quick measurement shows that the bolt-hole at the top is about 1/4-inch higher on the VX selector shaft. I believe that the shift linkage configuration may easily allow me to simply raise up the selector assembly by that amount with a spacer.

Think about it. As far as I've been able to determine, the Beta VX cars still used pretty much the same shifter mechanism that the normal Betas used and those standard Beta gearboxes will bolt right into a Scorpion or Montecarlo.

If nothing else, I think it would probably be easier to simply drill another hole in the shaft a bit further down and rework the top of the shaft than it would be to disassemble both boxes, ream the internal hole, then reassemble.

Perhaps I'm being too optimistic. We shall see.

[Wallace]

Correct ! My explanation is not too clear !! I just went about it in my usual bull in a china shop way so you could well be correct about a VX shaft being ok.

But a cheap adjustable reamer isn't expensive - I borrowed one from a firend !

I was putting in new bearings so had the box in bits for that - as well as blasting to clean it up. The rough school of engineering would ream it out anyway as a very small bit of ally swarf in the box wouldn't do any harm to anything !!!!

[Geoff T]

Hey DJ,
I just used the original Montecarlo clutch assy, and replaced the driven plate just cause it was easier to do now than when it was worn out! The clutch release bearing / arm is different on a VX box because they use a cable clutch, not hydraulic like the Monte. I am running the twin DCNF's I got off you on an otherwise standard 2L and the standard clutch is fine, even with the taller 1st gear. Just need a few more revs off the line to stop a bunny-hop!
I ended up rebuilding the VX box shortly after I installed it due to a worn 2nd gear synchro that I couldn't detect until it was fitted! I did this while the gearbox was still in place. In reality, all you need to swap out is the final drive crownwheel and pinion, but whatever gearset you use has to stay together as the VX box has a taller 1st gear cluster. I tore both boxes apart and built one good one as I discovered one of the diff spider gears had lost a tooth at some stage. (It was still in the bottom of the gearbox!). I guess if you are sure the VX box is a good one, you could try playing with the linkages to get them to work, but I'm not sure how the additional selector shaft height will affect the shift mechanism.
It's not really a big job to swap the casings over, as long as you have the two slpline sockets to undo the gearshaft nuts! I made one from a 1/2 inch drive socket and an hour on the grinder.

Geoff T

1982 S2 Montecarlo

[Tom McGaffigan]

DJ,
You will also need a big socket to remove the nut holding the selector shaft in the housing. As I recall it is 2 inches or larger in size. I machined the VX box selector shaft into the same correct configuration as the Scorpion selector shaft. My Scorpion one was all carved up from the use. Watch out for flying syncro balls from 5th gear.
Tom McGaffigan